Meningococcal bacteria can live outside body for a week

File photo / Thinkstock
File photo / Thinkstock

A study has challenged long-held beliefs about the survival of meningococcal bacteria outside the body, finding they can live for up to seven days.

In the most extensive study of its kind, researcher Claire Swain from the school of Biological Sciences at Victoria University in Wellington, spent 10 years researching different strains of the bacteria.

Previously it had been widely believed the bacteria could not survive for long periods outside the human body.

However, she found every strain tested could survive outside the body for periods of four hours to seven days, and environmental conditions were a key factor in bacteria survival rates.

The results highlighted the risk of contracting the disease through sharing things like drink bottles, glasses and cutlery, days after it had been infected.

"They may not even have to put the implement in their mouth to transfer the bacteria - sneezing on it might be enough,'' she said.

The relationship between temperature and humidity was important in the survival of bacteria, said Dr Swain.

"The New Zealand epidemic strain survived really well during winter and significantly worse during summer, which fits in with the seasonal epidemic rates of meningococcal disease in the western world.''

Dr Swain tested survival rates for a selection of strains on both plastic and glass, including the serogroup B strain which caused an epidemic in New Zealand in the 1990s and early 2000s.

She found the bacteria lasted significantly longer on glass than on plastic.

Dr Swain said her results show that different serogroups have different survival rates, but that was only one factor in their potency.

The findings were the first step towards identifying possible markers that could predict if a particular strain could be a strong survivor, and was therefore more likely to cause an epidemic.

- APNZ

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